London, 1817. Outside the Covent Garden Theatre, a crowd is desperate for a glimpse of actress Hannah Granville after her latest performance - including the Prince Regent himself. But before she emerges a gunshot sounds, and a man lies dead amidst the ensuing chaos. It proves to be Sir Roger Mellanby MP, whose political leanings towards social reform had made him many enemies not just at Westminster but within his own family. After a curt dismissal from the Bow Street Runners, Mellanby's friend Seth Hooper engages twin detectives Paul and Peter Skillen to investigate the MP's killing. Elsewhere, the assassin's own problems are just beginning ...